Electromagnetically operated ball-type injectors

ABSTRACT

Improved electromagnetically operated ball-type injectors having a simplified construction, comprising a protective casing, a core housed in the interior of the casing and comprising a fluidintake conduit, an excitation coil surrounding the core, a housing comprised between the cover and the core, and further comprising a ball adapted to close the injection conduit formed in the cover, the ball being acted upon by the excitation coil in opposition to a restoring elastic system mounted at the front of the core. The injector is especially intended for use for fuel injection in internal-combustion engines.

Lombard et al.

1111 3,865,312 1 51 Feb.- 11, 1975 [5 1 ELECTROMAGNETICALLY OPERATED 3,506,166 4/1970 Pooley 251 /139 x BALL TYPE [NJECTORS 3,567,135 3/l97l Gebert 239/585 3,738.578 6/1973 Farrell 239/585 [75] Inventors: Claude Lombard; Alain Dera, both of Bluancourt France Primary Examiner-M. Henson Wood, Jr. [731 Assignees: Regie Nationale des Usines Renault, Assistant ExaminerMichael Mar Billancourt; Automobiles Peugeot,- Attorney, Agent, or FirmStevens, Davis, Miller & Paris, both of, France Mosher [22] Filed: Dec. 26, 1972 1211 Appl. No.: 318,637 [571 ABSTRACT Improved electromagnetically operated ball-type in- [30] Foreign Applicafion Priority Data jectors havinga simplified construction, comprising a J 6 1972 F 72 0 protectlve casing, a core housed in the interior of the 9 'f 0327 casing and comprising a fluid-intake conduit, an exci- DBC. 15, l rancem. ation coil surrounding the core a housing comprised between the cover and the core, and further compris- [fi] 23968856525333 ing a ban adapted to close the injection conduit i 585 formed in the cover, the ball being acted upon by the 1 0 l 5 excitation coil in opposition to a restoring elastic systern mounted at the front of the core. The injector is especially intended for use for fuel injection in inter- [56] References cued nal-combustion engines.

UNITED STATES PATENTS 3,245,652 4/1966 Roth 251/139 11 Clam, 11 Drawmg Flgum l 1 V y 12 8 7 1 1 t 5 1/ n *&

J 11 II PATENTED 3.865.312

SHEET l UF 4 The present invention relates to electro-magnetically operated ball injectors intended to ensure the injection of a fluid, especially in internal combustion engines.

In devices of this type which are already known, the closure device constituting the valve regulates the flowrate in dependence on a number of parameters such as the force of the spring, the excitation current, the travel of the device and the centering of the various parts. In consequence, its structure is complex and for this reason necessitates accurate machining.

The invention has for its object to remedy this drawback by providing injectors having a valve with a simple structure in the form of a ball.

The invention also has for its object a supply of ball injectors which operate at high frequency and in which the flow-rate, which essentially depends on the time of the actuating impulse and on the shape of the injection conduit, is regulated in an accurate manner.

An injector according to the invention comprises a protective casing, a core housed in the interior of the casing and comprising a fluid-intake conduit, an excitation coil surrounding the core, a housing located between the cover and the core, and in which is provided a closure ball for the injection conduit, this ball being placed in the cover and being acted upon by the excitation coil in opposition to an elastic system mounted on the front of the core.

It, will be noted that the sections of passage of the fluid on the upstream side and around the ball, provided especially in the form of channels and the section of the seating on which the ball rests, are several times greater than that of the fluid outlet, in order that the flow-rate of the injector may depend only little on the lifting of the ball, on the excitation current and on the restoring force of the elastic system.

Other characteristic features and advantages of the invention will furthermore be brought out in the description which follows below of an example of the particular construction of an injector, given without any implied limitation, with reference being made to the accompanying drawings, in which:

FIG. 1 is a view in axial cross-section of the injector;

FIG. 2 is a cross-section taken along the line lIIl of FIG. 1;

FIG. 3 is a cross-section taken along the line Ill-III of FIG. 1;

FIG. 4 and FIG. 5 show two alternative forms of construction of the front portion of the core and the elastic restoring system;

FIG. 6 shows the arrangement of two injection conduits inside the cover;

FIG. 7 shows a further form of construction of the injector;

FIG. 8 is a transverse section taken along the line VIII-VIII of FIG. 7;

FIG. 9 represents an example of construction of the connector of the coil;

FIG. 10 shows the arrangement of an injector with two injection conduits;

FIG. 11 shows an alternative form of construction of the ball injector according to the invention.

The injector shown in FIG. 1 comprises a casing of magnetic material, in which a first portion forms the protective casing l and the second portion forms the core 2 of an electro-magnet. This core 2 comprises a fluid inlet conduit 3. At the extremity of the core, 2, a ball 4 of magnetic material, pushed by the elastic system 5 and forming a clapper-valve on its seating 6, made of non-magnetic material, for example of austenitic stainless steel, is arranged in the housing 7 formed in the cover 8 which fits on the casing l and constitutes a third portion of the main casing.

Under the action of the field created by the coil 9 placed on the support 10, the ball 4 is applied against the core 2 in opposition to the spring 5, and the fluid then flows through the channel 3, the grooves II, the housing 7, the grooves 12 and the injector hole 13.

The assembly now described shows one of the special features of the invention. The seating 6 and the ball 4 being placed in the cover 8, the latter is screwed in abutment on the protective casing l, a sealing joint 14 being placed between the cover 8 and the support 10, and the joint 14 being placed between the support and the protective casing l. The core 2 is introduced in abutment and is welded at 15. The regulation of the travel of the ball is then effected by unscrewing the cover 8 by the number of turns or fractions of turns which correspond to the desired value.

The ball 4 which is preferably hollow may be given surface treatments; it may be chromium-plated for example, in order to create a gap with the core 2 inthe open position of the valve, and thus avoids sticking due to remanent magnetism.

The extremity of the core 2 comprises an outer shoulder 2a against which is supported the elastic restoring system 5 for the ball 4, the extremity 2b of the core being flat and perpendicular to the direction of travel of the ball, the flow of fluid being ensured through the inlet conduit 3 and the grooves 11 and 12.

The ball 4 may also be wholly of magnetic metal, the fixed gap to avoid the effect of remanence being then constituted by a thin layer of non-magnetic material such as chromium, cuproberyllium, a cermet, etc. fixed on the extremity 2b of the core.

In another form of embodiment of the invention shown in FIG. 4, an added non-magnetic part 16 is placed in the center of the extremity of the core and also prevents the action of remanent magnetism.

The extremity of the core 2 represents an alternative form of the invention. In FIG. 4, the spring 17 is placed in the housing 18 formed in the core 2. In FIG. 5, the ball 4 rests on a shoe 20 which ensures a self-guiding action in the housing 7. The base of the restoring spring 21 is then advantageously located at the center of the core 2 in the cavity 22.

The ball 4 and the shoe 20 or one of-these two only,

are given a surface treatment. They are for example chromium-plated in order to prevent sticking by remanent magnetism. The shoe 20 having a flat face opposite the core 2 and a concave face opposite the ball 4 is interposed between the restoring spring 5, 17, 21 and the ball.

FIG. 6 shows an example of an arrangement of two injection conduits 23 and 23 which make it possible to ensure either the necessary flow with a single admission conduit or a distribution between two or more admission conduits.

FIG. 7 represents an alternative form of construction of the ball injector. This injector comprises a casing of magnetic material, a first part of which forms the protective casing 31, a second part forms the base 310. and

a third part 32 forms a conduit 33 for the admission of fluid into the valve. At the extremity of the core 32, a ball 34 of magnetic material pushed by the spring 35 to form a clapper valve on its seating 36, made of nonmagnetic material, for example of austenitic stainless steel or of cupro-beryllium, is arranged in the housing 37 formed in the cover 38, which is fitted on the protective casing 31 and forms the fourth part of the main casing. This casing is made of magnetic material of high induction quality.

Under the action of the field created by the coil 39 placed on the support 40, the ball 44 is applied against the core 32 in opposition to the spring 35, and the fluid then flows through the channel 33, the passage 41 formed in the tube.42, the housing 37 and the injection conduit 43.

The non-magnetic tube 42 arranged round the core 32 ensures the centering of the parts 32, 34 and 43. The tube 42 is rigidly fixed at 48 to 31 and 32 and at 49 to 36. A non-magnetic part 46 prevents the ball 34 from sticking to the core 32. Grooves 47 formed along the length of the core 32 reduce the eddy-current losses in the core. The ball 34 is preferably hollow and is made of magnetic stainless steel.

The connection of the wires of the coil is advantageously effected, as shown in FIG. 9, in the form of a flat flexible circuit such as a printed circuit 50 which begins at two points 51 and 52 of a ring 53 which is applied against the support 40.

FIG. 10 represents an example of mounting construction of an injector with two injection conduits 23 and 23' supplying simultaneously and respectively a number of admission conduits.

FIG. 11 represents an alternative form of construction'of the ball-type injector according to the invention. It is in fact important to prevent turbulence created by the instantaneous pressure existing in the admission pipe, which pressure varies from to more than one bar, from disturbing the flow at the nose of the injector.

In order to overcome this drawback, there is associated with the injector described above a nozzle constituted by a chamber fitted on the cover of the injector, into which discharges the conduit formed in the cover, an injection conduit being formed in the front face of the chamber, and a lateral opening having a diameter greater than that of the injection conduit being provided in the wall of the chamber.

By virtue of this arrangement, there is obtained through the lateral opening, a flow-rate definitely higher than that of the injection conduit, so that the residual pressure inside the chamber is negligible.

The advantages of the injector thus improved reside in that the pressure at the nose of the injector is equal to atmospheric pressure, in that the fuel pressure in the injector inlet conduit is obtained by comparison with atmospheric pressure, and for this reason the driving pressure of the fuel is independent of atmospheric pressure. A last advantage is that the flow-rate of pressureregulation air makes it possible to effect an emulsion of the outlet.

In FIG. 11, the nozzle, designated as a whole by 54,

is constituted by a cylindrical chamber fitted on the cover 8 of the injector or forming part of the cover. At the center of the front face 55 of the chamber is pierced an injection conduit 56. In the lateral wall of the chamber and close to the front face is formed an opening 57. The diameter of the opening 57 is 4 to times greater than the diameter of the opening 56. There'is thus obtained through the opening 57 a flow which is definitely higher than the flow through the opening 56. The pressure existing on the opening 57 is that of the filtered air drawn into the admission pipe.

What we claim is:

1. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit. an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein an extremity of said core comprises an external shoulder, against which is supported the elastic system acting on said ball, the extremity of said core being flat and perpendicular to the direction of movement of said ball, and the flow of fluid being ensured by the intake conduit and a plurality of grooves around said ball.

2. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and further comprising a non-magnetic piece located in the center of the core which comes into contact with said ball.

3. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intakeconduit,

and excitation coil surrounding saidcore, a cover, a

housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in oppositoin to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several time greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein a shoe, having a flat face opposite said core and a concave face opposite said ball, is interposed between the elastic system and said ball.

4. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage section comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and further comprising a non-magnetic tube mounted round said core and fixed on said core, said tube passing into the cover and ensuring the guiding of said ball while forming fluid passages round said ball, and a non-magnetic seating fixed on said tube.

5. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein a thin layer of non-magnetic material is added on the extremity of the core on the face of a shoe in contact with said ball.

6. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, whereinsections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein said ball is hollow and coated with a non-magnetic material.

7. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several'times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein the core comprises longitudinal grooves in the lower part thereof in order to reduce a slowing down operation due to eddy currents.

8. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein output wires of said coil are welded on a flexible flat circuit comprising a ring enclosing the central portion of said injector and fixing said circuit in position.

9. An injector in accordance with claim 8 wherein said flexible flat circuit is a printed circuit.

10. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and further comprising at least two fluid injection conduits respectively oriented towards each of the inlets of the admission conduits of an internal combustion engine.

11. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and further comprising a nozzle constituted by a I chamber fitted on the cover of said injectr,'into which tion conduit. 

1. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located betweeN the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein an extremity of said core comprises an external shoulder, against which is supported the elastic system acting on said ball, the extremity of said core being flat and perpendicular to the direction of movement of said ball, and the flow of fluid being ensured by the intake conduit and a plurality of grooves around said ball.
 2. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and further comprising a non-magnetic piece located in the center of the core which comes into contact with said ball.
 3. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, and excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in oppositoin to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several time greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein a shoe, having a flat face opposite said core and a concave face opposite said ball, is interposed between the elastic system and said ball.
 4. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage section comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the Excitation current and on the restoring force of said elastic system, and further comprising a non-magnetic tube mounted round said core and fixed on said core, said tube passing into the cover and ensuring the guiding of said ball while forming fluid passages round said ball, and a non-magnetic seating fixed on said tube.
 5. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein a thin layer of non-magnetic material is added on the extremity of the core on the face of a shoe in contact with said ball.
 6. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein said ball is hollow and coated with a non-magnetic material.
 7. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein the core comprises longitudinal grooves in the lower part thereof in order to reduce a slowing down operation due to eddy currents.
 8. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the Front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and wherein output wires of said coil are welded on a flexible flat circuit comprising a ring enclosing the central portion of said injector and fixing said circuit in position.
 9. An injector in accordance with claim 8 wherein said flexible flat circuit is a printed circuit.
 10. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and further comprising at least two fluid injection conduits respectively oriented towards each of the inlets of the admission conduits of an internal combustion engine.
 11. An electro-magnetically operated injector for fluid injection, especially in internal combustion engines, comprising a protective casing, a core housed in the interior of said casing and having a fluid intake conduit, an excitation coil surrounding said core, a cover, a housing located between the cover and said core and in which is provided a ball for closing a fluid injector outlet located within said cover, said ball being acted upon by said excitation coil in opposition to an elastic system mounted at the front of said core, wherein sections of passage of a fluid upstream of and around said ball and a section of a seating on which the ball rests are several times greater than that of the fluid injector outlet, said passage sections comprising channels, so that the flow rate of the injector depends only little on the lifting of the ball off the seating, on the excitation current and on the restoring force of said elastic system, and further comprising a nozzle constituted by a chamber fitted on the cover of said injector, into which opens the fluid injector outlet located in said cover, an injection conduit being formed in the front face of said chamber and a lateral opening, having a diameter greater than that of the injection conduit, being provided in the wall of said chamber, said lateral opening being at least four times greater than that of said injection conduit. 